Short pre-enrichment and modified matrix lysis. A comparative study towards same-day detection of Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen of particular concern in ready-to-eat foods. Different methodologies have been published in recent years, in order to reduce the time of analysis of this pathogen but, best case scenario, all these methods allow for next-day detection. There is permanent need in the food industry for faster methods capable of providing accurate results, without compromising the safety of the consumers, in order to cope with nowadays' intensive production system. In the present study, two sample treatment protocols namely, short pre-enrichment and matrix lysis, were compared to determine their suitability for same-day detection of L. monocytogenes. Both methodologies were sensitive, specific and accurate (100%), and allowed to obtain results in one working day. In addition to this, the results obtained matched those expected as observed by the Cohen's k value obtained (1.00). However, a the major difference was observed in their limit of detection (LOD95), as the short pre-enrichment allowed to detect L. monocytogenes in samples inoculated below 10 CFU/25 g, while the matrix lysis remained in the range of 10(5) CFU/25 g. These results indicate that whenever a zero tolerance is required, the short pre-enrichment protocol must be selected.

Automated summary

This study compared two sample treatment protocols, short pre-enrichment and matrix lysis, for the same-day detection of L. monocytogenes. The results showed that the short pre-enrichment method has a lower limit of detection, making it suitable for zero tolerance requirements.